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Finding the Fourth Proportional to 420.54, 630.59 and 142.81

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Solution

The fourth proportional to 420.54, 630.59 and 142.81 is: 214.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.54 : 630.59 = 142.81 : x
  2. Step 2: Convert to fraction form
    420.54/630.59 = 142.81/x
  3. Step 3: Cross multiply
    420.54x = 630.59 × 142.81
  4. Step 4: Simplify right side
    420.54x = 90,055.81
  5. Step 5: Solve for x
    x = 90,055.81/420.54
  6. Step 6: Final answer
    x = 214.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.